1. Field of the Invention
The invention is related to a semiconductor device having a resistor divider circuit for dividing a resistor, and more particularly to a divider circuit used for a high-voltage generating circuit of a flash memory.
2. Description of the Related Art
In order to satisfy requirements of high speed and low power consumption, NAND type flash memory uses a low power supply. Therefore, flash memory uses a high-voltage generated inside of a chip when performing programming or delete operations. During the programming operation, an inner high-voltage generating circuit can generate about 30V, when it does not provide a stable high-voltage to a block with a heavy load (memory cell array). For generating such a high-voltage, a voltage regulator can use a voltage divider circuit with a high resistor element to reduce power consumption, and the sink current is reduced.
In the prior art, namely Japan Patent publication No. 2004-140114, a first output setting circuit is installed between a reference voltage and a feedback node, and a second output setting circuit is installed between the feedback node and an output terminal. When the output terminal is coupled to a load, switches for the first and second output setting circuits are off, current flows through the path of low resistor element of the voltage divider circuit, and the voltage of the feedback node changes quickly according to the load. Therefore, unstable operation of the circuit due to parasitic capacitance associated with the resistor element is prevented. In addition, Japan Patent publication No. 2013-38234 discloses a voltage divider circuit including a resistor R1 and a resistor R2 coupled in series, and the resistors R1 and R2 are formed by diffusion regions in the well of the semiconductor substrate. By connecting the voltage division node in the diffusion region of the resistor R1 to the well region of the resistor R2, the variable rate of difference of the resistors R1 and R2 is suppressed.